What are Spring return & Non-Spring return actuator?

Actuators can be categorised based on what happens when power is removed, which are Spring return & Non-Spring return actuators.

Non-spring return actuator:

These are actuators, When the electricity or air pressure is withdrawn, non-spring return instruments will stay in their place. Usual valves work in such a way.

Spring return actuator:

This is an important category of valves. Spring return actuators will automatically be driven fully to one closed position or open position when the electricity or air pressure is removed.

Applications for using Spring return actuator:

A perfect example for the use of spring return actuators is an airhandler to open the heating coil valve and close the cooling valve whenever the fan is turned off.

During cold climate, the valve avoids melting of either coil and excessive horsepower cooling, dehumidification and pumping during hot weather. The valve installation is usually referred to as open or shut.

The normal position is that which occurs when power is removed. This is frequently denoted on mechanical or control drawings by making the abbreviation “N.O.” or “N.C.” next to the symbol for the control device.

A valve body is usually not shut or usually opened by itself. Only the setup of a spring return actuator provides a standard place for the damper or valve assembly. An exception to this are smaller unit valves with integrated actuators.